Field of the Invention
The present disclosure generally relates to an image forming apparatus, such as a copying machine, a printer, and a facsimile machine, in which an exterior cover is opened and closed to remove and replace a process cartridge mounted inside the apparatus.
Description of the Related Art
In a certain configuration of an image forming apparatus, an image bearing member (photosensitive drum) with a toner image formed thereon and an image forming unit (developing roller) are configured as a cartridge mountable on and removable from an image forming apparatus main body (apparatus main body) so that the replacement of consumables and other maintenance works can be easily performed.
In such cartridges, there is a contact development type in which development is performed by bringing the photosensitive drum into contact with the developing roller at the time of image formation. In a configuration discussed in Japanese Patent Application Laid-Open No. 2007-213025, to maintain a state where a photosensitive drum and a developing roller are in contact with each other, the developing roller is urged by an elastic member, disposed between a development unit and a drum unit of the cartridge respectively including the developing roller and the photosensitive drum, so that the developing roller comes into contact with the photosensitive drum. When the developing roller is separated from the photosensitive drum, the developing roller is moved to separate from the photosensitive drum by pressing the cartridge with a pressing member provided in the apparatus main body, and this state is maintained.
However, according to the configuration discussed in Japanese Patent Application Laid-Open No. 2007-213025 in which the developing roller is urged to come into contact with the photosensitive drum by the elastic member provided in the cartridge, it is necessary to provide an elastic member for generating an urging force in the cartridge. As a result, the size of the cartridge is increased. In a state where no cartridge is mounted on the apparatus main body, the developing roller is urged by the elastic member to come into contact with the photosensitive drum. Therefore, if this state is maintained for a long period of time, the frame of the cartridge, the developing roller, and the photosensitive drum may possibly be deformed. Therefore, in such a configuration, there is required a certain measure such as providing a member for restricting deformation in a state where no cartridge is mounted on the apparatus main body.
When the development unit and the drum unit are configured as different cartridges so that they can be separately mounted on and removed from the apparatus main body, it is basically difficult to provide an elastic member between the development unit and the drum unit.